1. Technical Field
The present invention relates to a method of purifying 8-isoprostane.
2. Related Art
8-isoprostane is a prostaglandin-like compound formed by oxidation of phospholipid contained in cell membrane or lipoprotein with free radicals. Oxidative stress in vivo can be noninvasively evaluated by measuring 8-isoprostane contained in a biological sample such as urine or serum. A kit for measuring 8-isoprostane by an immunoassay is also commercially available.
In analysis of 8-isoprostane contained in a biological sample, it is known that contaminants such as proteins is removed by a pretreatment in order to improve analytical precision.
In Japanese Laid-Open Patent Publication No. 2004-157119, it is described about a technique for carrying out a pretreatment in which a deproteinized and delipidated specimen is dissolved in a buffer mixed n-hexane, 2-propanol and acetic acid at a specific ratio, put on an NH2 column, washed, and eluted in order to measure the concentration of 8-isoprostane contained in a body fluid by an immunoassay.
In WO 2008/065895, it is described about a technique for removing contaminants and extracting an F2-isoprostane compound by a two-step solid-phase extraction employing solid-phase extraction supports having different solid-phase capacities. In WO 2008/065895, such a technique is described that solvent exchange for LC-MS/MS analysis, concentration in order to enhance analytical sensitivity and sample purification can be carried out simultaneously in a short period of time.